Due to the often life sustaining functions provided by implantable medical devices, a failure to maintain a positive connection between a lead which provides therapy to a body into which a device is implanted could be catastrophic. Accordingly the predominant concern in designing and implementing connector functions between medical leads and medical device bodies is to maintain firm and reliable locks on the connection between the parts.
Perhaps the most reliable mechanism to date is exemplified in U.S. Pat. No. 4,461,194 in which a tool such as a screw driver is used to rotatably urge a set screw against a lead body so that the lead body is deformed or maintained in position against a relatively undeformable bore. This set screw solution can also be adapted to provide electrical connection if the part of the lead to which the set screw is applied is metallic.
Numerous problems can arise with the use of tools in a operating room and the general feeling is the less that can go wrong the better. Over compression resulting in damage to lead bodies and connectors is one problem. The potential for lost of surgical instruments is another. Accordingly, tool less and setscrew less connecting systems will be preferred for implantable medical device connections to their leads if they are easy to use by a surgeon.
Two such Setscrew Less connector systems are seen in U.S. Pat. No. 4,860,750 issued to Frey et al, and U.S. Pat. No.5,413,595 issued to Stutz. In the Frey patent a slideable wedge member locks into place around the lead body, this slideable member having the effect of urging the lead body against the relatively immovable bore wall opposite the slideable member surface. By urging the slideable member into place until it reaches a locked position the surgeon can feel a click against the lock mechanism. In the 750 patent it is a detent into which a protrusion attached to the slideable member falls and locks when the slideable member is fully in place. An alternative wedge member is described with reference to Frey's FIGS. 12 and 13 in which a rotatable wedging cam is oriented into position using a screw head 83.
An alternative means of compressing a lead body into a lead bore without resort tools is shown in the Stutz patent. Here a channel provides slideable access to two opposed cam surfaces which force together a sphincter seal around the lead body.
None of these cited references or any other provide the surgeon with both tactile and visual confirmation of the locked in place connector. Accordingly to facilitate the process of implanting medical devices having leads associated with them the applicant herein provides such a mechanism and system.